Getting blisters on my plucking fingers

I dont know whats going on, I have been playing for close to ten years, and all of a sudden I have gotten really bad blisters on my index and middle plucking fingers the last two shows I have played.
I think it might be my strings, but not sure. I used to play Blue Steel strings all the time, then switched to some Wooten strings. I now switched back to Blue Steel and think these may be causing the problem.

Best guess? The Wooten strings are probably smoother and softer on the fingers than the Blue Steels, and when you switched back they roughed you up a bit. I found Blue Steels really rough when I tried them after using DR Lo-Riders for several years.

I've had a nice double-layer blister on my index for the last 2 weeks. Get 'em every time I put it down for awhile, then start gearing up for a rash of shows or a recording. It's not so bad once you play off the top layer and expose the next blister underneath it.